1. Field
Embodiments of the present invention relate to terminals with touch input devices, and more specifically, methods for reducing display lag between the touch input device and the display device.
2. Description of the Related Art
Display panels incorporating or coupled to touch sensor panels provide an interaction system for touch-enabled terminals such as mobile phones, tablet computers, laptop computers, and desktop computers. In such terminals, graphics are displayed on the display panel and a user can interact with these terminals by touching the screen (e.g., using an active stylus, a passive stylus, or a body part such as a finger), thereby providing an intuitive user interface.
Touch events detected by the touch sensor panels are typically processed by high level application software running on an application processor (AP) of the device. The many processing steps between the touch sensor panel and the AP and the non-deterministic processing time on the AP (including delays due to other computational tasks being performed by the AP) introduce high levels of latency (e.g., 70 to 100 milliseconds) that reduce responsiveness of the computing device to the user's touch inputs.
Some empirical studies have indicated that most humans can detect even a 30 millisecond asynchrony between senses, such as touch and vision. Delays of 50 to 200 milliseconds would be detectable to most of users of these computing devices, which can lead to increased user frustration due to the failure of computing of the device to immediately provide feedback to the user's input.
Recently, mobile phones having both a front touch sensor panel installed on a front face and a rear touch sensor panel installed on a rear face have been provided. In this case, the user frustration can be further increased due to the delays occurring on both the front touch sensor panel and the rear touch sensor panel.